CRP and Pleural effusion: Invasive respiratory device present (even intermittently) in the 48 preceding the onset of infection AND:- respiratory compromiseAND:- new infiltrate, consolidation or pleural effusion on chest x-ray AND at least four of:- temperature >38°C or < 36.5°C or temperature instability- tachycardia or bradycardia- tachypnoea or apnoea- dyspnoea- increased respiratory secretions- new onset of purulent sputum- isolation of a pathogen from respiratory secretions- C-reactive protein > 2.0 mg/dL- I/T ratio > 0.2